Michael J. Zelefsky, MD

I am a board-certified radiationoncologist and co-leader of Memorial Sloan Kettering’s Genitourinary Disease Management Team — a multidisciplinary group of physicians who work together to treat patients with urologic malignancies.

As a recognized expert in the field of radiation therapy, I am Chief of Memorial Sloan Kettering’s Brachytherapy Service. Brachytherapy, which we use to treat many types of cancer, is the delivery of radiation using seeds implanted directly in a tumor.

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Our prostate brachytherapy program, which I have helped develop and enhance since joining the staff in 1990, is known for its depth of experience and cutting-edge approach in treating men with prostate cancer. For patients with advanced or aggressive prostate cancer, I have significant expertise using high-dose-rate brachytherapy and temporary brachytherapy, in which patients receive several high-dose treatments either as a boost or as the sole treatment. I also have experience using brachytherapy in patients whose tumor has recurred after external-beam radiation therapy or seed implant, as well as expertise using image-guided stereotactic radiosurgery for areas of metastases (spread) such as bone or lymph nodes.

In addition, I was instrumental in pioneering the use of IMRT (intensity-modulated radiation therapy, which is computer-guided delivery of high doses of radiation directly to the tumor) and IGRT (image-guided radiotherapy, radiation beams targeted precisely to the tumor) for treating men with prostate cancer.

I am Editor-in-Chief of Brachytherapy, a medical journal that addresses all aspects of this sub-specialty, and Chairman of the National Patterns of Care Study for Genitourinary Cancers. I am a past president of the American Brachytherapy Society.

For my work in this field, I have been honored to receive several awards including the Boyer Award for Excellence in Clinical research, the Outstanding Teaching Award in the Department of Radiation Oncology at Memorial Sloan Kettering, the 2009 Henschke Medal (the highest award of the American Brachytherapy Society for achievements in Brachytherapy), and the 2009 Emanuel Van Descheuren Award for Excellence in Translational Research.

I lecture nationally and internationally about radiation treatments for prostate cancer.

aggressive (uh-GREH-siv)

In medicine, describes a tumor or disease that forms, grows, or spreads quickly. It may also describe treatment that is more severe or intense than usual.

Source: The National Cancer Institute's Dictionary of Cancer Terms(http://www.cancer.gov/dictionary)

brachytherapy (BRAY-kee-THAYR-uh-pee)

A type of radiation therapy in which radioactive material sealed in needles, seeds, wires, or catheters is placed directly into or near a tumor. Also called implant radiation therapy, internal radiation therapy, and radiation brachytherapy.

Source: The National Cancer Institute's Dictionary of Cancer Terms(http://www.cancer.gov/dictionary)

breast (brest)

Glandular organ located on the chest. The breast is made up of connective tissue, fat, and breast tissue that contains the glands that can make milk. Also called mammary gland.

Source: The National Cancer Institute's Dictionary of Cancer Terms(http://www.cancer.gov/dictionary)

cancer (KAN-ser)

A term for diseases in which abnormal cells divide without control and can invade nearby tissues. Cancer cells can also spread to other parts of the body through the blood and lymph systems. There are several main types of cancer. Carcinoma is a cancer that begins in the skin or in tissues that line or cover internal organs. Sarcoma is a cancer that begins in bone, cartilage, fat, muscle, blood vessels, or other connective or supportive tissue. Leukemia is a cancer that starts in blood-forming tissue such as the bone marrow, and causes large numbers of abnormal blood cells to be produced and enter the blood. Lymphoma and multiple myeloma are cancers that begin in the cells of the immune system. Central nervous system cancers are cancers that begin in the tissues of the brain and spinal cord. Also called malignancy.

Source: The National Cancer Institute's Dictionary of Cancer Terms(http://www.cancer.gov/dictionary)

clinical (KLIH-nih-kul)

Having to do with the examination and treatment of patients.

Source: The National Cancer Institute's Dictionary of Cancer Terms(http://www.cancer.gov/dictionary)

external-beam radiation therapy (...RAY-dee-AY-shun THAYR-uh-pee)

A type of radiation therapy that uses a machine to aim high-energy rays at the cancer from outside of the body. Also called external radiation therapy.

Source: The National Cancer Institute's Dictionary of Cancer Terms(http://www.cancer.gov/dictionary)

IGRT

A procedure that uses a computer to create a picture of a tumor to help guide the radiation beam during radiation therapy. The pictures are made using CT, ultrasound, X-ray, or other imaging techniques. IGRT makes radiation therapy more accurate and causes less damage to healthy tissue. Also called image-guided radiation therapy.

Source: The National Cancer Institute's Dictionary of Cancer Terms(http://www.cancer.gov/dictionary)

A procedure that uses a computer to create a picture of a tumor to help guide the radiation beam during radiation therapy. The pictures are made using CT, ultrasound, X-ray, or other imaging techniques. Image-guided radiation therapy makes radiation therapy more accurate and causes less damage to healthy tissue. Also called IGRT.

Source: The National Cancer Institute's Dictionary of Cancer Terms(http://www.cancer.gov/dictionary)

implant (IM-plant)

A substance or object that is put in the body as a prosthesis, or for treatment or diagnosis.

Source: The National Cancer Institute's Dictionary of Cancer Terms(http://www.cancer.gov/dictionary)

IMRT

IMRT is a 3-dimensional conformal radiation therapy planning and delivery tool that shapes the radiation dose distribution and minimizes the dose to normal structures. IMRT implies inverse planning algorithms (i.e., the physician determines radiation treatment parameters to maximize dose to the target and minimize dose to normal tissues, and the planning algorithm maximizes the adherence to these parameters by modifying the beam spatially and/or temporally). Spatial and temporal beam modification is often achieved by dynamically moving multi-leaf collimators. IMRT can also be achieved via custom-made beam compensators, which are derived from inverse planning algorithms. A novel way to deliver IMRT is tomotherapy, in which a bank of collimated leaves shutter open and closed while rotating around the patient in a spiral manner. The unifying principle of all IMRT planning and delivery methods is inverse planning. IMRT results in a greater deposition of low doses to normal tissue, which may increase the risk of second malignancies. Also called intensity-modulated radiation therapy.

Source: The National Cancer Institute's Dictionary of Cancer Terms(http://www.cancer.gov/dictionary)

Intensity-modulated radiation therapy is a 3-dimensional conformal radiation therapy planning and delivery tool that shapes the radiation dose distribution and minimizes the dose to normal structures. Intensity-modulated radiation therapy implies inverse planning algorithms (i.e., the physician determines radiation treatment parameters to maximize dose to the target and minimize dose to normal tissues, and the planning algorithm maximizes the adherence to these parameters by modifying the beam spatially and/or temporally). Spatial and temporal beam modification is often achieved by dynamically moving multi-leaf collimators. Intensity-modulated radiation therapy can also be achieved via custom-made beam compensators, which are derived from inverse planning algorithms. A novel way to deliver intensity-modulated radiation therapy is tomotherapy, in which a bank of collimated leaves shutter open and closed while rotating around the patient in a spiral manner. The unifying principle of all intensity-modulated radiation therapy planning and delivery methods is inverse planning. Intensity-modulated radiation therapy results in a greater deposition of low doses to normal tissue, which may increase the risk of second malignancies. Also called IMRT.

Source: The National Cancer Institute's Dictionary of Cancer Terms(http://www.cancer.gov/dictionary)

lymph (limf)

The clear fluid that travels through the lymphatic system and carries cells that help fight infections and other diseases. Also called lymphatic fluid.

Source: The National Cancer Institute's Dictionary of Cancer Terms(http://www.cancer.gov/dictionary)

medicine (MEH-dih-sin)

Refers to the practices and procedures used for the prevention, treatment, or relief of symptoms of a diseases or abnormal conditions. This term may also refer to a legal drug used for the same purpose.

Source: The National Cancer Institute's Dictionary of Cancer Terms(http://www.cancer.gov/dictionary)

multidisciplinary (MUL-tee-DIH-sih-plih-NAYR-ee)

In medicine, a term used to describe a treatment planning approach or team that includes a number of doctors and other health care professionals who are experts in different specialties (disciplines). In cancer treatment, the primary disciplines are medical oncology (treatment with drugs), surgical oncology (treatment with surgery), and radiation oncology (treatment with radiation).

Source: The National Cancer Institute's Dictionary of Cancer Terms(http://www.cancer.gov/dictionary)

National Institutes of Health (NA-shuh-nul IN-stih-TOOTS … helth)

A federal agency in the U.S. that conducts biomedical research in its own laboratories; supports the research of non-Federal scientists in universities, medical schools, hospitals, and research institutions throughout the country and abroad; helps in the training of research investigators; and fosters communication of medical information. Access the National Institutes of Health Web site at . Also called NIH.

Source: The National Cancer Institute's Dictionary of Cancer Terms(http://www.cancer.gov/dictionary)

oncologist (on-KAH-loh-jist)

A doctor who specializes in treating cancer. Some oncologists specialize in a particular type of cancer treatment. For example, a radiation oncologist specializes in treating cancer with radiation.

Source: The National Cancer Institute's Dictionary of Cancer Terms(http://www.cancer.gov/dictionary)

oncology (on-KAH-loh-jee)

The study of cancer.

Source: The National Cancer Institute's Dictionary of Cancer Terms(http://www.cancer.gov/dictionary)

prostate (PROS-tayt)

A gland in the male reproductive system. The prostate surrounds the part of the urethra (the tube that empties the bladder) just below the bladder, and produces a fluid that forms part of the semen.

Source: The National Cancer Institute's Dictionary of Cancer Terms(http://www.cancer.gov/dictionary)

prostate cancer (PROS-tayt KAN-ser)

Cancer that forms in tissues of the prostate (a gland in the male reproductive system found below the bladder and in front of the rectum). Prostate cancer usually occurs in older men.

Source: The National Cancer Institute's Dictionary of Cancer Terms(http://www.cancer.gov/dictionary)

radiation (RAY-dee-AY-shun)

Energy released in the form of particle or electromagnetic waves. Common sources of radiation include radon gas, cosmic rays from outer space, medical x-rays, and energy given off by a radioisotope (unstable form of a chemical element that releases radiation as it breaks down and becomes more stable).

Source: The National Cancer Institute's Dictionary of Cancer Terms(http://www.cancer.gov/dictionary)

radiation therapy (RAY-dee-AY-shun THAYR-uh-pee)

The use of high-energy radiation from x-rays, gamma rays, neutrons, protons, and other sources to kill cancer cells and shrink tumors. Radiation may come from a machine outside the body (external-beam radiation therapy), or it may come from radioactive material placed in the body near cancer cells (internal radiation therapy). Systemic radiation therapy uses a radioactive substance, such as a radiolabeled monoclonal antibody, that travels in the blood to tissues throughout the body. Also called irradiation and radiotherapy.

Source: The National Cancer Institute's Dictionary of Cancer Terms(http://www.cancer.gov/dictionary)

radiosurgery (RAY-dee-oh-SER-juh-ree)

Radiosurgery implies the delivery of a single, high dose of radiation using stereotactic techniques. Classically, for cranial radiosurgery, a rigid neurosurgical frame is attached to the patient’s skull, and a stereotactic localizing device is attached to the frame to allow for improved targeting accuracy. Commercial radiosurgery systems are available in which immobilization is achieved without a rigid neurosurgical frame. While there are innumerable commercial radiosurgery and stereotactic radiation therapy systems, all of these systems utilize the same underlying principles: (1) patient immobilization, (2) targeting accuracy, (3) delivery of high doses of radiation, and (4) heterogeneous dose distribution with a steep dose gradient. Commercial radiosurgery systems include Gamma Knife, which utilizes 201 radioactive cobalt sources positioned in a semispherical array, and Cyberknife, which utilizes robotics technology allowing the linear accelerator (LINAC) to track the patient position in real time during treatment. A standard LINAC can be equipped with cones attached to its head, allowing for circular collimation of the beam. The dose distribution from Gamma Knife, Cyberknife, or a standard LINAC equipped with cones is spherical, and thus treating nonspherically shaped targets requires the superposition of multiple spherical dose distributions. A LINAC equipped with multi-leaf collimators can also be used for radiosurgery, which allows more conformal beam shaping. Also called radiation surgery, stereotactic radiosurgery, and stereotaxic radiosurgery.

Source: The National Cancer Institute's Dictionary of Cancer Terms(http://www.cancer.gov/dictionary)

radiotherapy (RAY-dee-oh-THAYR-uh-pee)

The use of high-energy radiation from x-rays, gamma rays, neutrons, protons, and other sources to kill cancer cells and shrink tumors. Radiation may come from a machine outside the body (external-beam radiation therapy), or it may come from radioactive material placed in the body near cancer cells (internal radiation therapy). Systemic radiotherapy uses a radioactive substance, such as a radiolabeled monoclonal antibody, that travels in the blood to tissues throughout the body. Also called irradiation and radiation therapy.

Source: The National Cancer Institute's Dictionary of Cancer Terms(http://www.cancer.gov/dictionary)

significant (sig-NIH-fih-kunt)

In statistics, describes a mathematical measure of difference between groups. The difference is said to be significant if it is greater than what might be expected to happen by chance alone. Also called statistically significant.

Source: The National Cancer Institute's Dictionary of Cancer Terms(http://www.cancer.gov/dictionary)

skin cancer (skin KAN-ser)

Cancer that forms in the tissues of the skin. There are several types of skin cancer. Skin cancer that forms in melanocytes (skin cells that make pigment) is called melanoma. Skin cancer that forms in the lower part of the epidermis (the outer layer of the skin) is called basal cell carcinoma. Skin cancer that forms in squamous cells (flat cells that form the surface of the skin) is called squamous cell carcinoma. Skin cancer that forms in neuroendocrine cells (cells that release hormones in response to signals from the nervous system) is called neuroendocrine carcinoma of the skin. Most skin cancers form in older people on parts of the body exposed to the sun or in people who have weakened immune systems.

Source: The National Cancer Institute's Dictionary of Cancer Terms(http://www.cancer.gov/dictionary)

therapy (THAYR-uh-pee)

Treatment.

Source: The National Cancer Institute's Dictionary of Cancer Terms(http://www.cancer.gov/dictionary)

translational research (trans-LAY-shuh-nul reh-SERCH)

A term used to describe the process by which the results of research done in the laboratory are used to develop new ways to diagnose and treat disease.

Source: The National Cancer Institute's Dictionary of Cancer Terms(http://www.cancer.gov/dictionary)

tumor (TOO-mer)

An abnormal mass of tissue that results when cells divide more than they should or do not die when they should. Tumors may be benign (not cancer), or malignant (cancer). Also called neoplasm.

Source: The National Cancer Institute's Dictionary of Cancer Terms(http://www.cancer.gov/dictionary)

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